cm:Member: us-gaap:NonredeemablePreferredStockMember
| Nonredeemable Preferred Stock [Member] |
| us-gaap:NonredeemablePreferredStockMember |
| Preferred shares that are not redeemable before liquidation of the entity. Preferred shares may provide a preferential dividend to the dividend on common stock and may take precedence over common stock in the event of a liquidation. Preferred shares typically represent an ownership interest in the company. |
| cm:Member |
| [Member] (nonnum:domainItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:NonredeemablePreferredStockMember |